Not long ago , america depended on imports of liquefied natural gas .
不久前,美国还需要依赖液化天然气的进口。
That 's because the additional processing and shipping of liquefied gas would put even more greenhouse gas pollution into the atmosphere .
原因在于,额外的处理工序以及液化气的船运过程中将向大气中排放较多的温室气体。
It will soon start shipping liquefied natural gas from the gulf of aden , completing a $ 4 billion project begun less than four years ago .
它将马上开始从aden湾海运液化的天然气,完成3年多以前开始的价值40亿美元的计划。
Similar vessels are being considered for several projects in deep water around the world where piping gas back to land to be liquefied would be too costly .